1389921321 has 4 divisors (see below), whose sum is σ = 1853228432. Its totient is φ = 926614212.

The previous prime is 1389921287. The next prime is 1389921329. The reversal of 1389921321 is 1231299831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1231299831 = 3 ⋅410433277.

It is not a de Polignac number, because 1389921321 - 2⁹ = 1389920809 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1389921321.

It is not an unprimeable number, because it can be changed into a prime (1389921329) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 231653551 + ... + 231653556.

It is an arithmetic number, because the mean of its divisors is an integer number (463307108).

Almost surely, 2^1389921321 is an apocalyptic number.

It is an amenable number.

1389921321 is a deficient number, since it is larger than the sum of its proper divisors (463307111).

1389921321 is an equidigital number, since it uses as much as digits as its factorization.

1389921321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 463307110.

The product of its digits is 23328, while the sum is 39.

The square root of 1389921321 is about 37281.6485821107. The cubic root of 1389921321 is about 1115.9979726264.

The spelling of 1389921321 in words is "one billion, three hundred eighty-nine million, nine hundred twenty-one thousand, three hundred twenty-one".